During the operation of measuring devices, the functions are conventionally selected via operating keys. After a function has been selected, the value of an adjustment parameter, which is allocated to the corresponding function, can be altered by activating a rotary knob. If several possible adjustment parameters associated with the same function operate together as a parameter set, the individual adjustment parameters must be selected one after the other using a corresponding number of operating keys, so that the complete set a parameters has to be worked through. In the case of a measuring device with a comprehensive range of functions and an accordingly large number of individual functions and associated adjustment parameters, either a large number of operating keys is required or multiple definition of the individual operating keys is necessary.
A large number of operating keys and multiple definition of the operating keys combine with the increasing complexity of the functional structure to form a complicated system, which makes operation of the measuring device considerably more difficult in practice. In particular, it is not possible to gain a rapid overview, for example, of all the adjustment parameters associated with a specific function.
Regarding the technical background, reference must be made to U.S. Pat. No. 5,953,009. This document describes the allocation of trigger functions to a measuring channel of a digital oscilloscope by clicking and moving across the user interface icons which symbolise the trigger functions. However, the signal flow of individual functional units and the function of these functional units are not recognisable and cannot be selected on the user interface.